 |
 |
 |
 |
|
 |
 |
SAE J2735-Draft-Rev28 [issued: 11-10-08]
-
26 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
5. Message Sets
This section defines the structure of the DSRC message sets. Each message set shall be further divided into
specific messages and elements as defined in this clause and those that follow. Typically, these messages
are made up of message content internal to this document (made up of entries that are either atomic or
complex) and message content external to this document (from other functional areas and companion
volumes).
Definitions for these messages are presented in the following subclauses. The ASN is presented in a
section called "ASN.1 Representation," formerly called "Format." In a similar manner, the equivalent
XML expression is presented in a section called "XML Representation" which follows the translation rule
set cited in Clause Two (SAE J2630).
Regarding equivalent entries to be placed into a data registry. The mapping between data elements and
analogous meta data entries have been explained in other ITS stds. In addition, some meta information is
constant in this entire standard and need not be repeated with each entry here. These include the sponsor
and steward of the entries [SAE], the registration status [registered once the standard is adopted] and the
revision date [the date of the standards adoption]. The class name is always ITS.
The productions of ASN.1 which follow shall be considered normative in nature. While the majority of the
normative content is reflected in the actual syntax of the ASN.1 some entries also have additional
statements in the ASN.1 comments which shall be considered to be normative as well. In addition, the
commentary provided with each entry may also provide additional normative restrictions on the proper use
of the entry which shall be followed. The XML productions follow directly from the ASN.1 specifications
and the same rules shall be applied.
5.1 Message: MSG_Ala Carte
Use: A message which is composed entirely of message elements determined by the sender for each
message. The message is composed of two same content as found in the Part II section of the basic safety
message.
ASN.1 Representation:
AlaCarte ::= SEQUENCE {
msgID DSRCmsgID,
-- the message type
id TemporaryID OPTIONAL,
-- ID when needed
-- Part II,
partTwo PartTwoContent OPTIONAL,
... -- # LOCAL_CONTENT
}
XML Representation:
<xs:element name="alaCarte" type="AlaCarte"/>
<xs:complexType name="AlaCarte" >
<xs:sequence>
<xs:element name="msgID" type="DSRCmsgID" />
<!-- the message type -->
<xs:element name="id" type="TemporaryID" minOccurs="0"/>
<!-- ID when needed
Part II, -->
<xs:element name="partTwo" type="PartTwoContent" minOccurs="0"/>
<xs:element name="localAlaCarte" type="local:AlaCarte" minOccurs="0"/>
</xs:sequence>
</xs:complexType>